Your turn play should depend on villain's donking range to an extent, so it's useful to check the stat.

Your turn reasoning sounds decent, if you expect villain to barrel FD, then there is little point in betting, you might aswell hope to reach showdown.
His donk stat is useful because if he donks hands like QJ, TJ, TK, etc, there is stuff you can extract value from.

River fold is fine imo. Usually players don't take this line as a bluff.